Power tool



A. L. SOHM March 6, 1945 POWER IOOL s sheets-sheet 1 Filed Oct. 29, 1943v INVENTOR. .445950 1. 50/1/14, BY

ATTORNEY.

March 6, 1945. I SOHM 2,370,885

POWER TOOL Filed Oct. 29, 1945 3 Sheets-Sheet 2 INVENTOR 42, 250 1. 50/744,

ATTORNEY.

March 6, 1945. H 2,370,885-

' POWER TOOL Filed OCL. 29, 1943 5 Sheets-Sheet 3 "llllfllllllllllll II!INVENTOR. 445250 A. 50/1914,

&Z;;;7///, 117 9.

0 ATTORNEY.

Patented Mar. 6, 1945 'apnl e tit om er z9; 194s, seriarna: 508 ,268

(c1 1o*;13s)y.,

a allfilaim si This invention relates to power tools and has for anobject the provision of a power-driven tool of small compact, andinexpensive"designiwliicli is-capableiof performing with a; high'degreeof' efiiciency, numerous operations commonlyem-v ployedinmachinegshop. practice.

Aihrther object of my'invention is theprovision of'a power=driven toolwhich; while beingcapablev of affording; great convenience per forming awide varietyoi' mechanical operations such as grindingburrin'g; milling;and slotting; is particularly useful in connection with the operationsof drilling and tapping; I

A more detailed object in this" connection is the provision of I apower'tool of the character described adapted t'o'di'ivea drill at'the proper4 speedier itsoptimumoperationjand then to be adjusted soasto rotateatthe-reduced speed suit?- able forth-at size or tap forwhicnthe hole justdrilled'is of'th'eproper diameter toinsure the cutting'of'a satisfactorythread:

Figu're'3 is"a'idetairview'in' said' elevation of the gearing. alone-inthe; same positionas illustrated inFig;2.' I II v Figure 4 is a" viewsimilar to Fig. 3 but with the'partsmoved to the'respective po'sitionsoccupied therebywhen' a" tap is being" withdrawn:

Figure Bijs'a'trans erse; verticalj"sec'tionalviewtaken on aplane'indicat'edby*the"line5=-5 of Fig; 2 with the direction of' view'asindicated; and illustrating the locking plate in that position whereinit retains the driven shaft 'gutot direct connection with the'driving'sh'afti I Figure'di's a view'similar-to Fig, Sshcwlng thelocking, plate" moved to its intermediate position. I Figure 7 is aviwfsirnilar to j Fig: 2" showing the chanee'speed" gearing: disconnectedand the drivenshaftcoupledin'directdrive"tothe driving i A further"object of my' present invention is to provide means for" automaticallyreversing t he direction of'drive of themachine'upon completion of. a.tapping operation so as toicause withdrawal of the tap from the tappedhole.

A still further object I is to j design the-controls foroperatingthechanget-speed gearing in such a manner thatjthey are subject to:operation 'ouickly and easily, and-alsoso that thepossibilityofengagingboth the gearing and' the directdrivesimultaneous1y,is-positivelyprecluded;

, The invention'possessesother ob'jectsand-valtrable features, someoffwhich, with thoseenumerated, will be set forth'inthe' followingdose-rip tionof the preferre'dven bodimentof'my inven- "Figure -& isa-det a il View side elevation show} ing the manner of connecting thedriven shait" to the driving shaft-"indirect-.drive;

' Figure 9"isadetairviewin transverse; horizon tal section; the-plane ofsection being indicated bytheiine 9-90: Fig. 7'and the direction orv-iewbythe' arrows. I Specifically describing the preferred} embodiment of mypresentinvention; my improved pow-- tion illustrated in the"drawings"accompanying and forming, part "of" the: specifications. It" is toshowing made byjthe saiddrawings andidescripbe understoodthat ildoynotlimit'myself-to the v 4d)- tions as I'may adopt] variationsoi'the"preferred form within the scope ofimy'inve'ntion as defined by theclaims. I I

Referring to the'drawingsi Figure 1 a is a perspective viewofia powertool embodying the principles ofthe present invention showing theldevicemounted in operative relation on a. work benchwith "suitable guidingattachments vin. operativev association therewith.

' Figure 2 is an. enlargedivi'e'wof'apower'tool of the present.inventiongin lon'gitudinal, medial, vertical 1 section, v a1 portion.offth'e fi ure being n; axial alignment with the driving shaft Is and Ihas'mjounted upon its front end ,exteriorly of the v. v

broken away to reduce its size. In thisview'the v.parts are shown inthe. respective". positions} assumed thereby. for theneri'ormance. qftatapping ni I 1 having front and back 1egs-.8 and 9* respec 'tively,risingvertically therefrom; theselegs be} ing spacedapartsufiicientlytoprovide a'* gear chamber l=l-therebetween. Preferably 'anexten si'on l2" of" reduced lateral and vertical dimensions is providedupon the inner face ofeach' of the *l egs-t andato accommodate aremovablecover l-3 which enclosesthe-gear'chamber H;

I A driving-shaft s is; journalld in theback leg 9 and has-"a pulley H'-secured toitsouter" I edge; thisjpulley preferably being of the conical-7 type to provide a plurality "ofi steps It! so that" its drivingbelt l9can bemounted in-anyor a plu rality of optional positions thereupon andthereby make various'i'possibilities in" the speed at which the drivingshaft IK'will be rotatedi A i frame 6 achuclrfflfor other means 'formounting a working tool 'such" as'a; drill, tap" or the likein axialalignment thers'ha'ft' 2'1; Both-shafts l6 l HdZI extend inward fromtheir supporting legs 8 and respectively tb a position substan- [tiallyadjacenteach other appljOx im'ately midway I betweenthetwo'legs;

A' di?iving.' gear 23 is rigidly mounted" upon the" frame; and a drivengear 24 is mounted upon the extreme inner end of the driving shaft l6for free rotary and axial movement with respect thereto. A coil spring25, under compression between two gears 23 and 24, urges the gear 24toward the limit of its motion-to the left as viewed uponFigs. 2 and 7.Motion of the gear 24 in this direction is limited by a disk 21 which isaffixed to the associated end of the shaft l6 by, i

The gears23 and 24 are provided with hubs 3| and 32 respectively,extending toa screw 28.

ward each other and provided with ratchet teeth 33 and 34 respectively,on theirproximal faces; Hence means are provided for keeping the drivengear 24 connected to the driving gear 23 to be rotated therewith byshifting the driven gear 24- to the right as viewed upon Figs. 2 and"?against the action of the spring 25. Fig. 8 illustrates the ratchetteeth 39 on the forward face of the hub 32 of the driven. gear24; Thedriven shaft 2|, in addition to being revoluble' in its supporting leg8, is capable of axial movement also. Before the shaft 2| :reachesthelimit of its inward move- I ment, the teeth 38 on the innerface of thehead 3! will engage the 'teeth"39 on the driven gear .24; but after thisengag'ementhas occurred the driven shaft 2| can bemoved still furtherinwards thuscarrying the driven gear 24 with it to effect engagementbetween the ratchet teeth 33 and34, with the result that the drivenshaft 2| is connected in direct drive to the driving shaft J6- Fig. 8illustrates the associated parts in this position. 3

Means are driven shaft 2| in its innermost position, i. e.,

n its pos'ition of direct drive. A flange 4| is preferably revolubly.mounted on the shaft 2| just provided for releasably locking the Iforward of the front leg 8; 3 When the shaft 2| is in its innermostposition the flange4| preferably bears against the front face o f theleg 8.

I A locking plate 421s slidablymounted onthe front face of the leg 3 asby a pair of opposed .fianges 43. Pr eferably this locking plate 42 exxtends on both sides of the protruding forward end 1 ,of the shaft 4|, anaperture being formed in the plate 42 through which the shaft 2|extends. Moreover, this aperture 44 is large enough ,to receive theflange 4| and thereby permit the shaft 2| to be slid inward when thelocking plate 42 has been slid to that position in which it iscompletely removed from the path of the flange 4|. After the shaft 2|has been slid to its inner- .most extreme position, the plate 42 can beslid downward still further to move a detent 46 in front of the flange4|;so as to prevent the shaft 2| from moving outwards again from itsinner- ',most position. This detent is securedto the locking plate 42 atthe upper edge of theaperture 44. Hence, it movesinto retainingengagement with the flange 4| when the locking plate 42- is in itslowermost position, illustrated in Fig.3.

A countershaft 5| is journalled in the frame "6 extending acrosstheg'ear'chamber below and parallelto the driving and driven shafts I6 and2|, respectively. However, in addition to being revolubly mounted, thecountershaft 5| is also capable of axial movement from its innermostposition as illustratedin Fig; 2, to its outer- "most or forwardposition as illustrated in Fig. 7.

"Large and small gears 53 and54g'respectively,

are rigidly aflixed to the countershaft 5| in such position thereon thatwhen the countershaft is in its innermost position (Fig. 2) the largergear 53 is enmeshed with the driving gear 23 and the smaller gear 54 isenmeshed with the driven gear 24, provided'the driven gear 24 is pushedto the limit of its movementtowards the front of the machine. As will beexplained more fully hereinbelow, the driven gear 24 will have to occupythis extreme forward position before the countershaft 5| can be slid aftto bring its gears 53 and 54 into alignment with the gears 23 and 24.

Another gear .56, preferably having the same number of teeth as the gear54, is mounted upon the countershaft 5| adjacent the inner face of thefront leg 8. This gear 56 is splined to the countershaft 5| so as toconnect the gear to the shaft for rotation therewith but to permitrelative axial movement therebetween. One con venient manner ofproviding this connection is through the expedient of a pin 51 rigidwith the gear 56 and extending through a slot 58 in the countershaft 5|,which slot is extended axially of the countershaft 5| a suflicientdistance to permit the shaft 5| full reciprocation through its necessarystroke without interference from the pin 51 although the gear 56 remainsin contact with the inner face of the front leg 8. A coil spring 59,under compression between gears 54 and 56, continually urges thecountershaft 5| aft, i. e., towards its innermost position asillustrated in Fig. 2.

The gear 56 is permanently enmeshed with an idler gear 6| which isrevolubly mounted on a pin 62 rigid with the front leg 8; and this idlergear 6| is enmeshed with a gear 63 which is journalled for free rotationupon the driven shaft 2|. The hub 64 of this gear 63 is provided withratchet teeth 66 which are normally retained out of engagement withcomplementary ratchet teeth 51 on the forward face of the head 31 bymeans of a coilspring 68 under compression between gear 63 and the head31. However, since the driven shaft 2| is axially slidable it can bepulled forward in its journal, compressing the coil spring 68, until theteeth 5! on the head 3! are brought into engagement with the teeth 66,it being understood of course that such engagement cannot take placeuntil after the teeth 38 on the opposite face of the head 31 have beendisengaged from the teeth 39 on the driven gear 24. Since the idler gear6| is interposed between the gear 63 and the gear 56 which is rotatedwith the countershaft 5| the gear 53 will, whenever the countershaft 5iisin its innermost position, be rotated in the opposite direction fromthat in which the driving shaft l6 and the gear 23 and 24 carriedthereby rotate. Hence when the driven shaft 2| is inits innermostposition, engaging the head 31 with the driven gear 24, the chuck 22will be rotated in a forward direction; but as when the shaft 2| ispulled forward to its outermost position engaging-the head 31 with thereverse gear 63 the chuck 22 will be rotated in the reverse direction. v

Accessible upon the forward, exposed end of the countershaft 5| is aknob 16 which'provides'a convenient fingerhold whereby the countershaft"5| can be pulled forward against the action of the coil spring 59,moving the countershaft from the position wherein it is illustrated inFig. 2 I to that of Fig. 7.

The function of the spring 59 of course is continually to urge thecountershaft 5| inward to its Fig. 2 position wherein the gears5| and 54za aum ot the countershaft enmesh the. gears 23 and. respectively;However, means; are provided for preventing such-inward motion ofithecountershaft until after. the connection'of the. driven shaft 2| to thedriving: shaft IS in direct. drive is broken. 'Toward this end thelocking plate 4 2 is extended: downward past the countershaft 5|,preferablybeing formediwith a second aperture 11- through whichthenforward. end of the coun-v tershaft 5|; extends. The upperwedge ofthis aperture? is defined by a detentflll preferably bifurcated by anotch 19 large enough. to receive the eountershaft 5| therein to seatthe detent l'figbehindxthe knob '16 (see Fig. 7). The thick. .ness. ofthe detent 18 is. sufiicient to. hold the :countershaft 5| in itsextreme forwardposition when thusengaged behind the knob 16.. .Con-

sequentlywhenever thelocking plate 42 is in its lowermost position (Fig.7). the .countershaft .51 will be, in its extreme. forward position withits gears-53. and 54 disengaged from the. gears 23 and 24;. y

.izFI'he extra thickness. of the detent 1'8: lrequisite 'to. retain the.countershaft 5| in its extreme forward; position as described, hastheadditional function of supporting the locking. plate 42 in itsuppermost position and disposing a third detent 80 which is affixed atthe lower edge of the aperture 4.4 of the locking plate 42. behind theflange 4| on the driven shaft 2|. .It. is clear therefore, that so longas the locking plate 42 is. in. its highest position the driven shaft.2| is, positively retained against being pushed inward far enough tocause the engagement between the teeth 33 and 34 which is necessary toestablish .direct drive. It. will be understood therefore that therelationship between the knob and the locking plate 42 is suchthatwhenever the countershaft 5| is in its innermost position'therebyengaging the-change speed. gearing, the. possibility of connecting thedriven shaft 2| to the driving shaft I6 is positively precluded, therebyproviding positive assurance against damage to thereto. An axial hole 8|is drilled into the driving shaft 16 from its inner end. The screw 28which-serves to anchor the disk 2'I-upon the. ;.end of the shaft I6 alsoacts as a plug to' close the end of the hole 8!. Aradial'hole, 82 in theshaft |6 establishes c'ommunicationbetween the axial hole,8| and an oilhole 83 extending downward in the rear leg 9 from its upper end toandthrough the bearing. 84 in which the shaft 6| is journalled. Hence asthe. shaft [6 rotates,the

hole 82 will come into registry with the oilhole .83 once during eachrotation permittingtoil in the oilhole 83 to flow into the center, holeor reservoir 8| Another radial hole 85 is provided adjacent the innerend of theshaft l6 establishing communication between the reservoir 8|and the outer surface of the shaft l6 at a point thereon frictionallyengaged by the revolublymounted driven gear H.

Figure 1 illustrates a' preferred manner .of

.. mounting the machine of the present invention to afford thegreatestconvenience in performaingtbe operations of. drilling andtapping. The.

Tdevice isthere illustrated as being mounted upon a: suitable supportsuchsas; av work bench 9.1;. 'An 7 electric motor .912is mountedunderneath the supporting surface. 9|, the. driving pulley .53 of themotor 9-2 being connected to. the; pulley ll by a. driving belt 94,preferably a. V-belt, in 131160011? ventional manner. A bracket 96- ismounted on thebench 9| in front ofthe machine, and preferably with anopening Blinx the bracketxin aligna .ment: with the axis of rotation ofthe. chuck-22.

- Also:,, a stopbracket 8811s mounted in front of work bench 9,1.

the machine as by av pair .of'studs 99 threaded into; the front leg 8and extending horizontally forward therefrom. to support the stopbracket 9.8 which alsois provided with an opening l8| in axial alignmentwith the chuck22 so that. a

drill or; a tap I02 mounted in the chuck 22 can extend freely throughtheopening: lfll as illustrated. i

The. bracket 96 is preferably mounted for ready removal, towards whichend-it preferably is affixed to a plate, I03 adaptable to rest. upon theupper surfacev of the bench 9|, and. to be lo.-

cated at a predetermined distance from the ma.- chine as by a pair ofspacedcleats 104., I05. In the modificationillustrated, the cleats14,105 are shown as being non-.adjustably affi-xed to the This bracket.96 serves as a n convenient; support for any suitable jig (not shown)which may be used not only to'supp'ort the work but also to locateitwith respect to the ng tool'which: is: being: operated by the retatinchuck 22. Moreover as the jig mayserve as a. guide to assure. movementof the. work toward. and away from'the working tool in ac.-

curate parallelism with the axis of the tools rotation when.suchoperations asdrilling and tappins are being performed and accuratelyperpendicular with respectto that. axis when such operations as milling,slotting and the. like are .being performed. v j

e a o p et a a ar numb r of; metal plates f'si en size. are eac to berov ded with. a a edh l at a i e o a ion on ach'pl tehe acme "the 011 11122 and the m tor 92 then. s d, it

being understood that. the machine is connected 2 in direct drive, 1,cl, the teeth 34; engaged with the teeth .33 so thatthe ,chuck 22 isrotated at the, samespeed asthe driving shaft I6. Each P ate may then bedrilled either by holding the plate and pressing it manually against thedrill] or by placing the plate accurately in predetermined position upona jig carried by the. bracket .56. .The stop bracket 98 affordsconvenience as a depth gage to. assure a curately drilling the I n orderto facili at a nin a under tand ine of the mann r in whi hthe power to-1 o th pres t i ven n Qn ates,,. ns e for. am-

.n iate s ze f m l o the. pro er operationo the-part cular tab to bemployed is moun ed n hole to the required depth, it beingunderstoodAfter the hole. has been drilled to. thedesired depth, preferably in allof the pieces'to be operated upon, the motor '92 is stopped, the drillremoved from the chuck 2.2 and in place of the drill a tap 'l02 mountedin the chuck 22.as.i1lus'- trated in Fig- 1. The depth gage 98 shouldthen be adjusted in accordance with the length oil thetap M12, as willbe: readily understood.

Then, in order to causethechuck. 22torotate' that. the. stop bracket 98.is adjustable and can Qbe'v locked in selected position by manysuitable.locking means,z.not shown. 1

is the disengagement of the detent 46 from in front of the flange 4|which permits the spring I 26 to press the driven gear 24 forward andthereby effect disengagement of the ratchet teeth 34 from the ratchetteeth 33. That is to say, these parts are moved from the positionsthereof illustrated in 'Fig. 7 to their positions illustrated in Figs. 2and 3.

The upward movementof the locking plate 42, however, should be continueduntil the lowermost detent I8 is lifted from behind the knob 16,

whereupon the spring 59 will press the countershaft inwards. In thismanner, the gear 53 is enmeshed with the gear 23, and the small gear 54becomes enmeshed with the large driven gear 24, thus'establishingindirect drive; i. e., connection is established between the driving andthe driven shafts l6 and 2|, respectively, to cause rotation of thelatter at reduced speed.

Then, with the proper size of tap mounted in the chuck 22, the motor 92again should be started. One of the metal plates which previously hasbeen drilled is then placed against the end of the tap M2 in suchposition that the tap enters the previously drilled hole. Here again thestep of placing and guiding the work may be performed manually orthrough the expedient of a jig (not shown) rigidly supported in properposition by means of the bracket 96. If the depth gage 98 has beenproperly set the work being tapped will, when the tap 102 has cut itsthread to the proper depth in the drilled hole, make contact with thebracket 98. This will arrest inward motion of the work, i. e., motion ofthe metal plate toward the chuck 22. Thereafter the chuck 22 willcontinue to rotate but for only a very short interval, and the tap I02will continue to thread itself into the work,

drawing the chuck 22 and the driven shaft 2| outwards. The effect ofthis outward motion of the shaft 2|. will be to draw the head 31 towardsthe front leg 8 from its position in which it is illustrated in Fig. 3to that of Fig. 4. Consequently the teeth 38 of the head 31 becomedisengaged from the teeth 39 of the driven gear 24; and the teeth 61 onthe opposite face of the head 31 move into engagement with the teeth 66on the hub 64 of the gear 63 which, as explained hereinabove, is beingrotated in reverse direction. Consequently the chuck 22 will bereversely rotated as long as thisengagement between the head 31 and thegear 63 prevails, and the tap will be withdrawn from the hole in whichthe operation ofcutting threads now has been completed.

When it is desired again to connect the machine in direct drive, thepreviously described manipulation of the locking plate 42 is reversed.The first step is that of pulling the countershaft 5| forwards bygrasping the knob 16. Due to the extra thickness of the detent 1B, whichrides upon the upper edge of the knob 16 when the machine is connectedin indirect drive, the looking plate 42 is held in its most elevatedposition until the countershaft 5| has been withdrawn to the limit ofits forward movement, thus pro- :viding positive assurance that thedirect drive cannot become engaged until after the gears 53 and 54 havemoved to their Fig. 7 position, i. e., out of engagement with the gears23 and 24 respectively, it being borne in mind that so long as thelocking plate 42 is thus elevated the detent 1B is disposed behind theflange 4| (see Fig. 2), retaining the driven shaft in its extremeforward position as illustrated in Fig. 2 while the machine is.connected in indirect drive. As soon as the countershaft 5| has beendrawn forward, the locking plate 42 can be moved downwards to theposition thereof illustrated in Fig. 6 wherein a gage mark I thereonaligns itself with an indicator 2 on one or both of the guide flanges43. In thisconnection it should be mentioned that preferably themounting of the stop plate 42 within the guide flanges 43 issufliciently free to permit the plate 42 to drop by its own weight. Whenin the Fig. 6 position the detent 80 will have passed out from behindthe flange 4| and the uppermost detent 48 will come to rest upon theperiphery of the flange 4|. The operator should then, by grasping thechuck 22,'press the shaft 2| inwards. This will compress the spring 26and bring the teeth 34 on the hub 32 of the gear 24 into engagement withthe teeth 33 on the hub 3| of the gear 23 and thereby reestablish directdrive.

As an added feature, convenient means are provided for the removablesupport of additional working tools such as an emery wheel, millingcutter, or the like, and operating them by means of the machine of thepresent invention. For this purpose an axial hole |2| is provided in theextreme after end of the driving shaft Hi. This hole |2| is providedwith internal threads I22 preferably of left hand pitch therebyproviding convenient means for supporting and driving a suitable arborto serve as the spindle for numerous types of working tools such asthose mentioned.

I claim:

1. In a power tool of the character described, a frame comprising frontand back legs spaced apart to provide a gear chamber therebetween, adriving shaft and a driven shaft journalled respectively in said frontand back legs in co-axial alignment and extending to a position adjacenteach other within said chamber, said driven shaft being axially slidablewith respect to said front leg and extending therethrough to theexterior of said frame, means carried by theouter end of said drivenshaft for securing a working tool thereto, means carried by the innerend of said driven shaft for releasably coupling it to said drivingshaft and thereby establishing direct drive when said driven shaft is inits innermost position, speed-change gearing operably mounted in saidchamber, means operable to connect said gearing to both of said shaftsto vary the speed at which said driven shaft turns, a detent movableoptionally into or out of the path traversed by said gear-connectingmeans for releasably retaining said gears out of their connectingposition, and means operably coupled to said detent for retaining saiddriven shaft in its outermost position until said gearing has been movedout of its connecting position.

2. In a power tool of the character described, a frame comprising frontand back legs spaced apart to provide a gear chamber therebetween, adriving shaft and a driven shaft journalled respectively in said frontand back legs in co-axial alignment and extending to a position adjacenteach other within said chamber, said driven shaft being axially:slldable with respect to said front deg and extending therethroughtoithe exterior of :said frame, ,meansi-carried .by the outer .-end ofposition, speed-change gearing :operablymounted in said chamber, meansoperablesto connect said gearing to both :of said rshafts to vary thespeed at which said vdriven shaft turns, adetent amov- .able optionallyinto or foot of the path trave-rsed by said gear-connecting'imeans.forrelea-sablyzre :taining said-gears out of their;connectingaposition,

and means on said driven shaft-locking :said detent :in that ,positionwherein said. detent :retains ssaid gears out oftheirgconnecting:position,

:said adetent-loc'king xmeans ibeing releasable only after said. rdrivenshaft has-moved to its outermost position. I

--3. In a power tool of itheacharacterwdescribed,

a frame comprising front :and backlegs spaced apart to provide :agear'ohamber :therebetween,

a driving shaft and .ac'drivenzshaft .journalled-xrespective-ly in.-said front and'aback legs inco-axi-al to {said drivengear 1-170 berotated thereby; said :countershaft :being 'axiallyslidable, saidcounter? shaft gears being disengaged from said driving alignment andextending :toa position adjacent eachaothenwithin saidchamber,said-drivenishaft being axially slidable withrespect to saidfront leg and extending therethrough to the exterior of saidoframe,,means carried by the outer :end of said driven shaft for securing aworking tool thereto, :meanscarrled-by the inner endiof said drivenshaft for lreleasably coupling it to said driving shaft andthereby-establishing :direct drive "when said drivenxshaft -=.is:-at itsinnermost position, speed-change-gearing operablyimounted in saidchamber,meansnoperable to connectasaid gearing to both of saidshafts tovary the speed at which said driven shaft turns a'rshoulderwon saiddriven :shaft,wandadetentrmovable into the path of said shoulderaonlywhen said driven-shaft is in its innermost-position.

e. ,In a power .tool =.o-f theta-character described,

I a framehavingza gear chamberthereimadriving shaft and a driven'shaftrevolubly mounted'in co-a-xial alignment therein, said driven shaftbeing axially m0vab1e and extending to the ex terior of said frame :forconnection to K azworking tool, means operable \whensaid driven shaft.is

in its innermost position :for coupling :it .to said driving shaft, :3,countershaft ,rjournalled' inssaid frame parallel to said driving and.driven shafts, a large and-asmall gear mixed to said countershaft, :adriving .gearxon said :d-riving shaft, a 55 driven 1 gear, meansconnecting :said driven shaft being axially movable and extending to theexand driven gears when said countershaft isin zone endof its axialmovement and said large gear .being enmeshed with said driving shaftgear and :said small gear being enmeshed with said driven shaft gearwhen said countershaft is at the other end of its axial movement, springmeans urging said countershaft to said positionbf engagement -.of :saidgears, .and releasable means for locking said counter-shaft in its saidposition of disengagement of said gear. i

=6. In a power toolof the character described, a :frame having aiigearchamber therein, a driving shaft and :a drivenshaft .revolubly mountedin co raxial alignmenttherein, said driven shaft 'beeing-zaxiallycmovame and extending to :the exterior ofssaid'frame :forconnection to a working tool, means operable when :saiddriven shaft isin its innermost position for couplingit to saiddriving shaft, :a:countershaft journalled in said.:frame parallel to said driving anddriven shafts, adarge and :a small igear :afiixed to said "countershaft,"a driving gear on said driving :shaft, a driven gear, meansconnecting.said-zdrivenshaft to said driven gear to :be v.;rotate'dthereby, said countershaft being axially :slidable optionally to lenmeshits gears with 'said driving :and driven :gears or to disengage them,and-means operable to hold said driven shaft 1 in its innermost:position and said countershaft in itssaid-:positionsci-disengagementofrsaidgears. y s

a '7. In 'aipower .tooliofthecharacter described, a .frame having a:gear. chamber therein, a driving shaft and i2, driven .zs'haft:revolubly' .mounted in :co-a'xi al alignment therein, said driven shaftberingfaxialiymovableand"extending to the exterior of -saidframeaforiconnection to.:a working'tool,

,means operable when said driven shaft is in its innermost position forcoupling it to saiddriving shaft, :21. coun-tershaft :journalled in saidframe to said driven gear to be rotated thereby, :said .countershaftbeing axially slidable optionally to .enmesh its gears with said driving:and driven gears or to disengage them,wandgmeans.; for:re-

terior of said frame for connection to a Working I tool, means operablewhen said driven shaft is in its innermost position for coupling it tosaid driving shaft, a countershaft journalled in said frame parallel tosaid driving and driven shafts, a large and a small gear affixed to saidcountershaft, a driving gear on said driving shaft, a driven gear, meansconnecting said driven shaft parallel ,totsaid driving and-drivenshafts, a large zahdsa smallbgear affixed :to said\ countershaft, a'drivin'gagear on said drivingzshaft, a drivengear, meansrconnectingsaiddriven 'shaftto' said driven gear *tobe I-rotated thereby,.saidcountershaft-bea ;-ing::axial1y:slidable optionally to enmesh'its 'gearswith saiidadriving and :driven gears or" to disenggagexthem, springim'eans urgingsaid driven shaft to 111135 outermost'position, springmeans urging said countershaft to tits said position "of engage,- .ment'of "said gears, randp rel'easable means common to both said drivenshaft'and'said countersh'aft .resisting action :of both-of said spring"means. i

B. ..In;a power tool :of thecharacter described-a ,framelrhaving :agear-chamber therein, 'a driving rsha-ft andia driven'shaftrevolubly'mounted 'in co- .:axial alignment therein, said idrivenshaft being "axi'allyimovable and extending to the exterior of meansoperable when said driven shaft is in its innermost position forcoupling it to said driving shaft, a countershaft journalled in saidframe parallel to said driving and driven shafts, a large and a smallgear affixed to said countershaft, a driving gear on said driving shaft,a driven gear, means connecting said driven shaft to said driven gear tobe rotated'thereby, said countershaft being axially slidable optionallyto enmesh its gears r w1th said driving and driven gears or to disengagethem, spring means urging said driven shaft to its outermost position,spring means urging said countershaft to its said position of engagementof said gears, a locking plate slidably mounted on said frame adjacentboth said driven shaft and said countershaft, a shoulder on said drivenshaft, a shoulder on said countershaft, and detents on said lockingplate engageable with said shoulders to releasably hold said drivenshaft in its innermost position and said countershaft in its saidposition of disengagement.

9. In a power tool of the character described, a frame havin a gearchamber therein, a driving shaft and a driven shaft revolubly mounted inco-axial alignment therein, said driven shaft being axially movable andextending to the exterior of said frame for connection to a workingtool, means operable when said driven shaft is in its innermost positionfor coupling it to said driving shaft, a countershaft journalled in saidframe parallel to said driving and driven shafts, a large and a smallgear afiixed to said countershaft, a driving gear on said driving shaft,a driven gear,

means connecting said driven shaft to said driven gear to be rotatedthereby, said countershaft being axially slidable optionally to enmeshits gears with said driving and driven gears or to disengage them,spring means urging said driven shaft to its outermost position, springmeans urging said countershaft to its said position of engagement ofsaid gears, a locking plate slidably mounted on said frame adjacent bothsaid driven shaft and said countershaft, a shoulder on said drivenshaft, a shoulder on said counter shaft, and detents on said lockingplate engageable with said shoulders to releasably hold said drivenshaft in its innermost position and said countershaft in its saidposition of disengagement, said detent associated with said countershaftshoulder remaining in holding relation therewith as said locking plateis slid toward its unlocking said countershaft, a shoulder on saiddriven shaft, a shoulder on said countershaft, detents on said lockingplate engageable with said shoulders to releasably hold said drivenshaft in its innermost position and said countershaft in its saidposition of disengagement, said detent associated with said countershaftshoulder remaining in holding relation therewith as said locking plateis slid toward its unlocking position until after said detent associatedwith said driven shaft shoulder has been disengaged therefrom, a secondshoulder on said driven shaft, and a detent on said locking plateseating behind said second shoulder when said locking plate is in itsunlocking position to restrain said driven shaft against inwardmovement.

11. In a power tool of the character described, a frame having a. gearchamber therein, a driving shaft and a driven shaft revolubly mounted inco-axial alignment therein, said driven shaft being axially movable andextending to the exterior of said frame for connection to a workingtool,

means operable when said said driven shaft is in its innermost positionfor coupling it to said driving shaft, a countershaft journalled in saidframe parallel to said driving and driven shafts,

' a large and a small gear aifixed to said counterposition until aftersaid detent associated with said driven shaft shoulder has beendisengaged therefrom.

10. In a power tool of the character described, a frame having a gearchamber therein, a driving shaft and a driven shaft revolubly mounted inco-axial alignment therein, said driven shaft being axially movable andextending to the exterior of said frame for connection to a workingtool, means operable when said driven shaft is in its innermost positionfor coupling it to said driving shaft, 2. countershaft journalledin'said frame parallel to said driving and driven shafts, a large and asmall gear affixed to said countershaft, a driving gear on said drivingshaft, a driven gear, means connecting said driven shaft to said drivengear to be rotated thereby, said countershaft being axially slidableoptionally to enmesh its gears with said driving and driven gears or todisengage them, spring means urging said driven shaft to its outermostposition, spring means urging said countershaft to its said position ofengagement of said gears, a locking plate slidably mounted on said frameadjacent both said driven shaft and shaft, a driving gear on saiddriving shaft, a driven gear, means connecting said driven shaft to saiddriven gear to be rotated thereby, said countershaft being axiallyslidable optionally to enmesh its gears with said driving and drivengears or to disengage them, spring means urging said driven shaft to itsoutermost position, spring means urging said countershaft to its saidposition of engagement of said gears, a locking plate slidably mountedon said frame adjacent both said driven shaft and said countershaft, ashoulder on said driven shaft, a shoulder on said countershaft, detentson said locking plate engageable with said shoulders to releasably holdsaid driven shaft in its innermost position and said countershaft in itssaid position of disengagement, said detent associated with saidcountershaft shoulder remaining in holding relation therewith assaidlocking plate is slid toward its unlocking position until after saiddetent associated with said driven shaft shoulder has been disengagedtherefrom, a second shoulder on said driven shaft, and a detent on saidlocking plate seating behind said second shoulder when said lockingplate is in its unlocking position to restrain said driven shaft againstinward movement, said shoulder on said countershaft being arranged tomove into the path of said detent associated therewith when saidcountershaft moves to its said position of engagement of its gears andthereby prevent release of said driven shaft by said detent associatedwith said second shoulder until said countershaft has been withdrawnfrom its said position of engagement of its gears.

ALFRED L. SOHM.

